feat(nix): add darwin support in flake

not enabling it in ihaskell make nix flake check fail for jupyterWith

Print where kernel is installed

improve flake by distinguishing different goals (development vs final executable vs with a jupyter environment)

we used to expose just the ihaskellEnv. Also added devShell and attribute set for 921. I've renamed some of the packages on the same model as haskell-language-server.

IHaskellPrelude imports most of it

Remove imports

to make the buildlogs clearer

to fix build issues

Handle plugin initialization using :set -fplugin module

Handle plugin initialization using :set -fplugin .. Previously plugins were (almost) silently ignored

For jupyter

flake.nix now:
- expose an overlay to be used by for instance jupyterWith
- disabled tests 'cos failing
- bring haskell-language-server though it seems to choke on codebase

* .github/workflows/nix.yml: build release-{9.0,9.2}.nix as well

* release-9.2.nix: update

* Fix more hash mismatches

* release-9.2.nix: update

* .github/workflows/nix.yml: don't test for release-9.2.nix

* .github/workflows/nix.yml: fix comment indentation